A 52-year-old man who died in a downtown St. Paul parking ramp Monday evening fell unconscious during a prolonged struggle with a Church of Scientology employee he was attempting to rob, authorities said.

Officers responded to the ramp at 505 N. Wabasha Street, which is attached to the church, around 7 p.m. on a report of an assault. They found the assailant, who has yet to be identified, lying on the ground, unresponsive.

The man was taken to Regions Hospital, where he later died. His exact cause of death is unknown.

Investigators believe the man targeted a 49-year-old employee heading to work that night, near the ramp’s elevator lobby. The victim told authorities that the suspect had his hand hidden his jacket, intimating a handgun.

A struggle ensued as the victim repeatedly called for help. Fellow church workers rushed to his aid.

“At some point, with their assistance, he gained control of the robbery suspect and held him on the ground until police arrived,” said St. Paul police spokesman Sgt. Mike Ernster.

The victim suffered minor injuries to his hands and face. No weapons were ever found.

Several witnesses were interviewed at police headquarters Monday night, but all were released. No arrests have been made in the case.

Parts of the attack were caught on nearby surveillance footage. The investigation remains ongoing.

Liz Sawyer covers breaking news, crime and corrections for the Star Tribune. She previously wrote about suburban life in the south metro.